Aging tungsten light characteristics?

[chris jordan]

I'm noticing a dramatic increase in contrast put out by my tungsten bulb, combin ed with a decrease in intensity. Given the age of the bulb (2+ years), its a mat ter of time before it blows. Does anyone know if tungsten sources begin to shift toward "magenta", or know what exactly is occuring in the aging process? Just c urious. Thanks,

Chris

[Scott Walton]

When it is time to change the bulb in your enlarger, it does have a tendency to shift to the red/magenta side. At work we have a system for all enlargers to talk with each other called the R System. We monitor everyday due to the differences everyday.... Chris, we change bulbs sometimes every 4 months due to the R values drastically getting different. As the bulb burns out it will get warmer (going to the red spectrum). When this happens, you will be fighting a loosing battle with no consistency later when reprinting if you keep track of your color numbers. Get a number of bulbs and have them on hand.

[chris jordan]

That makes sense. Thanks!